The invention is directed to a fuel injection apparatus in which air is provided to the fuel in the injection valve to prepare the fuel for mixturing in the air intake tube downstream of the injection valve. A fuel injection apparatus is already known in which preparation air is fed to the fuel to be injected immediately before its injection into the intake pipe. However, the known device has the disadvantage that during idling, too great a quantity of preparation air is fed into the injection valve so that high idling rpms result. An overall reduction of the air supplied to the injection valve would enable a lowering of the idling rpm but would also cause a deterioration of the full-load operation fuel transport.